1. Field of the Invention
The present invention refers to a process, to a device and to the related system for automatically continuously packaging products, particularly graphic products, through heat-sealed plastic films.
2. Discussion of the Related Art
Hereinbelow the present invention will be described as applied to the packaging of graphic products such as magazines, printed matters, fascicles, newspapers, texts, books, etc. with different formats, but obviously it can be applied to any product adapted to be packaged in a heat-sealed plastic film.
Various devices are known in the art for dragging graphic products, that allow horizontally or vertically translating such products with respect to the ground. In particular, dragging and sealing pliers are known that are adapted to transversally seal heat-sealed plastic films. Such pliers are usually composed of lower striker pliers, on which a mat abuts that conveys the products around which the film to be heat-sealed has been wrapped; the lower pliers are adapted to cooperate with spring-actuated upper pliers equipped, on their lower face, with a hot wire that seals and cuts the film. When the two upper and lower pliers assume a closed working position, the upper pliers are pushed downwards and the hot wire with which they are equipped press onto the film and have as abutment the mat and the lower pliers, on which they abut for heat-sealing and cutting.
Systems for wrapping plastic films and for sealingly heat-sealing them are known for packaging graphic products. In particular, in the so-called longitudinal sealing, a hot roller is present that, by rotating on the length of overlapped film, activates its sealing in order to make a film that longitudinally wraps a product. The hot rotating roller works in cooperation with a fixed abutment blade that can be found below the films. The roller can be inserted immediately after the film bending device and can be connected thereto.
GB-A-2 233 305 discloses a method of wrapping various types of articles by means of a stretchable plastic film, and a machine for carrying out said procedure corresponding to the preambles of claims 1 and 3, respectively.
U.S Pat. No. 5,689,942 discloses a drive motor controlling apparatus for use in packaging machines.
FR-A-2 379 436 discloses a packaging machine for printed matter and its related process.